HPLC-FPD INSTRUMENTATION FOR THE MEASUREMENT OF THE ATMOSPHERIC DIMETHYL SULFIDE PRECURSOR BETA-(DIMETHYLSULFONIO)PROPIONATE

Instrumentation has been specifically developed for the measurement of beta-(dimethylsulfonio)propionate (DMSP), a compound implicated as a major precursor of atmospheric dimethyl sulfide. The instrument links the separation and identification possible by ion-exchange HPLC with selective postcolumn hydrolysis and quantitative name photometric detection. Compound selectivity is therefore gained from three independent characteristics: retention time behavior, base hydrolysis resulting in the production of a volatile sulfur compound, and sulfur-specific detection. The instrumentation described in this paper therefore provides the basis for the first reliable identification and quantitation of DMSP at trace levels. The 3 sigma detection of the prototype instrument, using a 200 mu L injection volume, was 2.2 x 10(-7) mol of DMSP dm(-3) or an absolute injected mass of 6 ng of DMSP. This corresponds to 36 pg of S . s(-1). The instrument has been employed in the measurement of DMSP in marine macroalgae.